Biochemical Cascade of Phototransduction

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on Biochemical Cascade of Phototransduction

Overview Phototransduction is the series of biochemical events that leads from photon capture by a photoreceptor cell to its hyperpolarization and slowing of neurotransmitter release at the synapse. This overall…

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Cornea and Sclera

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on Cornea and Sclera

Introduction The outermost, fibrous tunic of the human eye consists of the cornea and the sclera ( Fig. 4.1A,B ). Both are soft connective tissues that provide structural integrity to…

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Functions of the Orbit and Eyelids

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on Functions of the Orbit and Eyelids

Introduction The cranium protects the brain and provides scaffolding for facial structures. During primate evolution, the orbits were enlarged and reoriented toward the front of the face. This, along with…

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Formation and Function of the Tear Film

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on Formation and Function of the Tear Film

Tear film overview The tear film overlays the ocular surface, which is comprised of the corneal and conjunctival epithelia and provides the interface between these epithelia and the external environment….

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Signal Processing in the Outer Retina

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on Signal Processing in the Outer Retina

Introduction Rod and cone photoreceptors transduce light, and they operate over different levels of illumination and chromatic ranges. In the vertebrate retina, there is a single type of rod and…

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Light Adaptation in Photoreceptors

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on Light Adaptation in Photoreceptors

Vision from starlight to sunlight The human visual system operates effectively over an enormously wide range of intensities, of at least a billion-fold, from around 10 −4 cd m −2…

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The Synaptic Organization of the Retina

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on The Synaptic Organization of the Retina

The basic architecture, signal flow, and neurochemistry of signaling through the vertebrate retina is well understood: photoreceptors, bipolar cells (BCs), and retinal ganglion cells (RGCs) are all thought to be…

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Sensory Innervation of the Eye

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on Sensory Innervation of the Eye

Introduction Somatosensory innervation of the eye is provided by the peripheral axons of a small number of primary sensory neurons located in the trigeminal ganglion (TG). Most sensory axons enter…

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The Lens

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on The Lens

Introduction The optical properties of the ocular lens are a critical determinant of overall vision quality. As a transparent specialized epithelial tissue, the lens contributes to the overall and dynamic…

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The Extraocular Muscles

Jun 29, 2024 by in OPHTHALMOLOGY Comments Off on The Extraocular Muscles

Introduction The extraocular muscles (EOM) are a complex group of skeletal muscles located within the bony orbit. They function in a highly coordinated manner to perform conjugate eye movements, maintain…

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